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Calhoun Vision’s revolutionary LAL shows tremendous promise for cataract surgery


By Larry Haimovitch

Medical Device Daily Contributing Writer

May 5, 2014

BOSTON — The annual meeting of the American Society of Cataract and Refractive Surgeons (ASCRS; Reston, Virginia) took place here over the past few days and, as usual, showcased technologies that promise to significantly improve patient outcomes while boosting the profitability of the ophthalmic surgeon and the manufacturers as well.

According to the market research firm Marketscope (St. Louis) the global cataract surgical market and related supplies like intraocular lenses (IOLs) had estimated sales of about $7 billion in 2013 and is forecasted to grow at approximately 7% per year for the next few years. This rate is well above the typical medical device market.

Approximately 3.6 million cataract surgical procedures occur annually in the U.S. with an additional 20 million eyes treated outside this country.

Parenthetically, cataract surgery is the most commonly performed Medicare procedure.

Although cataract surgery is remarkably safe and regarded as highly efficacious, various surveys have shown that about 40% of cataract patients are dissatisfied with their results. Specifically, it has been demonstrated in many studies that about 50% of patients have a 0.5 diopters (D) shortfall from the targeted refractive goal. This may result in the need for glasses or secondary laser enhancement surgery to achieve the targeted refraction correction.

Another perspective is provided by Warren Hill, MD, a highly respected ophthalmic surgeon at East Valley Ophthalmology (Mesa, Arizona). Hill has gathered data over several years that less than 1% of all cataract surgeons achieve a 90% rate of less than 0.5D to their targeted correction.  Further, only 20% of surgeons attain a 75% rate within 0.5D of the intended correction.

This ‘dirty little secret” of cataract surgery contrasts to the robust clinical results of LASIK, where it is believed at least 85% of LASIK patients are estimated to achieve the intended refractive goal (typically 20/20) or better. Moreover, virtually all 100% are at 20/40.

Intraoperative aberrometry, a diagnostic technology which provides the cataract surgeon with data to make a more accurate intraocular lens selection during the surgery, has been gaining significant market traction in recent years.

Privately owned, venture capital-backed Wavetec Vision (Aliso Viejo, California) is the clear-cut industry leader, with an installed base of its ORA brand in excess of 300 systems. Its extensive clinical data, which has been presented at several ophthalmic meetings in the recent past, demonstrates that this technology improves visual outcomes.

Another contender in this field, privately-owned Clarity Medical Systems (Pleasanton, California) has developed an exciting and competing system called HOLOS. Its exhibit booth at this meeting was packed, as physicians were eager to see this new system in action. Commercial shipments of HOLOS are slated to begin in the second half of 2014.

Another approach to improving visual outcomes from cataract surgery has been developed by privately-funded Calhoun Vision (Pasadena, California). Its Light Adjustable Lens (LAL) is a revolutionary concept in the field of cataract surgery and intraocular lenses, employing a unique post-implantation “tweaking” that will adjust for any deficiencies in the initial IOL decision.

The proprietary LAL system employs a unique combination of Calhoun’s biocompatible, photosensitive materials called macromers and a customized digital light source. The latter consists of a 365 nanometer ultraviolet light source, projection optics and a control interface that is mounted on a standard slit lamp. The photosensitive silicone LAL is quite similar to a standard monofocal IOL and is implanted using standard cataract surgery techniques.

When the patient returns for their follow-up visit, typically 17 to 21 days later, the physician assesses the refractive correction and if it is not exactly as intended pre-surgically, the lens is exposed to Calhoun’s proprietary light source for 40 to 150 seconds. This causes the macromers to react, changing the shape and therefore the power of the IOL. The LAL is the world’s first intraocular lens that can be modified post-cataract surgery, with one to two visits, with the goal of tailoring the refractive correction precisely to the patient’s individual visual requirements.  

Although the LAL concept was first conceived over a decade ago, Calhoun has struggled with a plethora of technical challenges and the product development has taken much longer than initially predicted. Nevertheless, the company has made enormous strides in recent years, with CE Mark achieved in 2007.

In the U.S., it commenced its pivotal FDA trial in June 2013 and has now enrolled over 200 eyes in the study. The trial will enroll at total of 600 patients (400 LALs, 200 standard IOLs) at 18 sites and could be completed by the end of 2014. With one year follow-up, mandated by the FDA, final FDA approval could occur in the first half of 2017.

Peer-reviewed published clinical data from a German study of 121 patients, reported in the December 2011 issue of Ophthalmology, with 18-month follow-up demonstrated that 88 percent of subjects who received the LAL achieved distance vision of 20/20 or better without glasses. In the same study, 97 percent of treated eyes came within 0.25 diopters of the intended refractive target.

At a well-attended evening symposium here on Sunday night, several renowned ophthalmic surgeons expressed tremendous excitement for this approach. Although the company was reluctant to divulge the full data set for its U.S. enrollees to date, it did disclose data at this meeting from one trial site, the Jones Eye Clinic (Sioux City, Iowa). A total of 12 eyes have been treated, with 10 of the 12 attaining 20/20 or better vision. According to one of the speakers, Doyle Stulting, MD, Woolfson Eye Institute (Atlanta) this data is highly correlated with the results of the Phase 2 FDA trial, where 83% of the patients were within 0.5D of their intended correction.

Stulting also pointed out that the LAL system is highly effective in correcting for astigmatism, saying that the LAL “shows efficacy in treating for astigmatism much better than a toric IOL.” Indeed, this attribute was emphasized by other internationally-based ophthalmic surgeons, who have had extensive experience with the LAL.

Arturo Chayet, MD, of Codet Vision Institute (Tijuana, Mexico) discussed a potentially blockbuster concept which he termed  “Adjustable Blended Vision” (ABV). ABV is achieved by using the LAL system to increase the depth of focus via a customized corneal spherical aberration (SA) changes. SA, which is caused in part by the aging of the cornea, results in imperfect vision.

At his clinic, Chayet has treated 40 eyes in his ABV clinical study and reported tremendous results, with his patients enjoying excellent binocular distance, intermediate and near vision. The specific data, with comparison to the widely used ReSTOR MultiFocal IOL, is displayed in the table below.


        



Chayet concluded his talk saying that the LAL system “delivers outstanding

simultaneous near, intermediate, and distance visual acuity.” He further opined that “binocular customization of the amount of induced spherical aberration through Calhoun Vision’s ABV is the future of presbyopia correction.”

A prominent offshore scientist, Pablo Artal, PhD, from the Laboratorie de Optica, Universidad de Murcia (Spain) has assisted Calhoun with the development of the LAL technology for several years. His medical team has implanted over 350 eyes since 2007. He is also a proponent of the ABV approach, noting that the LAL “allows for optimum refractive outcomes . .  . at all distances.” He further noted that in a small study at his clinic, the ABV technique compares favorably to a diffractive tri-focal IOL.

Vance Thompson, MD, Vance Thompson Vision (Sioux Falls, South Dakota), one of the LAL investigators in the pivotal trial and a highly respected ophthalmic surgeon, reported “amazing refractive accuracy” with the LAL system.

He further gushed that “this is the most exciting clinical research I am involved with . . . and I cannot wait to offer this to my patients.”

American Society of Cataract & Refractive Surgery 2014

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